February 13, 2015

Pat has asked that I make his problem set available for you now so that you get practice working with balancer chromosomes early and have a chance to clarify your understanding with him and with the TAs. This problem set will be due March 6th.

In lecture Pat pointed out that an X chromosome balancer does not carry a lethal mutation and instead carries a recessive female sterile mutation (in addition to inversions and viable dominant visible mutation). Describe how a lethal mutation on the X chromosome can be stably carried in a stock with such a balancer and explain why it won’t work if the balancer has a lethal mutation. Hint – just draw it out and remember that males are XY.